Electrode for lead-acid battery

Abstract

The present invention relates to a lead-acid battery Comprising a positive and a negative electrode, each having a current collector comprising an expanded grid, characterized in that at least one of the positive electrode and the negative electrode contains an organic binder in an active material layer at an edge portion thereof. This makes it possible to suppress an internal short circuit resulting from the separation or abnormal growth of an active material due to repeated charge/discharge, thereby remarkably prolonging the cycle life of a lead-acid battery.

1. A lead-acid battery comprising a positive electrode and a negative electrode, each having a current collector comprising an expanded grid,
 characterized in that at least one of said positive electrode and negative electrode contains an organic binder in an active material layer, said organic binder being contained only at a circumferential edge portion of said active material layer, 
 wherein the organic binder comprises at least one of butyl rubber and styrene rubber. 
 
     
     
       2. The lead-acid battery in accordance with  claim 1 , wherein said butyl rubber contains butyl isocyanate. 
     
     
       3. The lead-acid battery in accordance with  claim 1 , wherein said expanded grid includes at least one hole extending from a first surface to a second surface, said active material layer being included in said at least one hole. 
     
     
       4. The lead-acid battery in accordance with  claim 1 , said active material layer includes first and second surfaces on opposite sides of said active material layer and a third surface extending from said first surface to said second surface in a thickness direction of said active material layer, said circumferential edge portion including said third surface and only a portion of said first and second surfaces. 
     
     
       5. A lead-acid battery comprising a positive electrode and a negative electrode, each having a current collector comprising an expanded grid,
 characterized in that at least one of said positive electrode and negative electrode has a porous resin layer formed on a side surface of an active material layer, said active material layer includes first and second surfaces on opposite sides of said active material layer and said side surface extends from said first surface to said second surface in a thickness direction of said active material layer, a portion of said porous resin layer formed on said side surface extends from said first surface to said second surface, said porous resin layer being formed only at an edge portion of said active material layer, wherein said edge portion includes said side surface and only a portion of said first and second surfaces. 
 
     
     
       6. The lead-acid battery in accordance with  claim 5 , wherein said porous resin layer comprises butyl rubber. 
     
     
       7. The lead-acid battery in accordance with  claim 6 , wherein said butyl rubber contains butyl isocyanate. 
     
     
       8. The lead-acid battery in accordance with  claim 5 , wherein said porous resin layer comprises butyl rubber and styrene rubber. 
     
     
       9. The lead-acid battery in accordance with  claim 5 , wherein said expanded grid includes at least one hole extending from the first surface to the second surface, said active material layer being included in said at least one hole.